Estimating the position of a device, such as a mobile smartphone or an electromagnetic signal source, is becoming more important with the advent of location based services and electronic navigation tools. A number of different positioning technologies are available, but none of these positioning technologies are fully accurate or fully reliable under all circumstances.
Satellite position system (e.g. Global Positioning System (GPS)) modules which are capable of receiving data from a plurality of satellites to identify their position typically require a line of sight between a plurality of satellites and a satellite positioning system receiver to operate reliably. When such a line of sight is unavailable, such positioning modules may not be able to determine positions to a sufficient level of accuracy (if at all).
Alternative positioning system modules such as triangulation based positioning system modules capable of estimating the position of a device using signals received from base stations of a cellular telephone network (e.g. 2G, 3G, 3.5G or 4G mobile communications network) are not always usable/accurate where, for example, access to the cellular telephone network is poor, patchy or unavailable.
Furthermore, positioning system modules capable of estimating the position of a device using data measured from a number of electromagnetic signal sources of known location can be inaccurate because errors in the estimated locations of electromagnetic signal sources cause errors in the estimated positions of the device.
Thus none of the above positioning systems is completely accurate and reliable. Indeed the accuracy of these positioning systems varies typically depending on the environment in which the device whose position is being estimated is located. Inaccuracy and unreliability is typically amplified when the device whose position is being estimated is located in an indoor region.
Accordingly, improving the accuracy of existing positioning systems is therefore desirable, particularly for use in indoor regions.